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• avcodec/magicyuv : Fix edge case of building Huffman table

  23 septembre 2020, par Andreas Rheinhardt

  avcodec/magicyuv : Fix edge case of building Huffman table
  The MagicYUV format stores Huffman tables in its bitstream by coding
  
  the length of a given symbol ; it does not code the actual code directly,
  
  instead this is to be inferred by the rule that a symbol is to the left
  
  of every shorter symbol in the Huffman tree and that for symbols of the
  
  same length the symbol is ascending from left to right. With one
  
  exception, this is also what our decoder did.
  The exception only matters when there are codes of length 32, because
  
  in this case the first symbol of this length did not get the code 0,
  
  but 1 ; e.g. if there were exactly two nodes of length 32, then they
  
  would get assigned the codes 1 and 2 and a node of length 31 will get
  
  the 31-bit code 1 which is a prefix of the 32 bit code 2, making the
  
  Huffman table invalid. On the other hand, if there were only one symbol
  
  with the length 32, the earlier code would accept this un-Huffman-tree.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/magicyuv.c

• Kodi building from source - gnutls not found in pkg-config path

  31 mai 2023, par user_0525

  I am using raspup (puppylinux on raspi) and building kodi inside depends folder of source via bootstrap, configure, make as mentioned on the github.

  


  Everything was going fine with make until it bumped gnutls not found in pkg-config path while configuring for ffmpeg. Log of last couple of lines are at pastebin. I can paste whole 2256 lines log if required.

  


  I have gnutls in pkg-config path. With command pkg-config gnutls --cflags I get the paths -I/opt/xbmc-deps/arm-linux-gbueabi-debug/include -I/usr/local/include/p11-kit-1.

  


  I have also checked and libunistring-dev is also installed, as it was suggested on some answers.

  


  I have even built and installed ffmpeg from source, still I am stuck at this error.
I tried getting help from ffmpeg mailing list but they said it's a kodi issue so they can't help. I also posted the problem on Kodi forum but didn't get any solution.

  


  config.log from ffbuild is at https://pastebin.com/WZEndxRN.

  


  Any help please...

  


• Building FFMPEG for Visual Studio development

  28 juillet 2016, par gboy

  I’m trying to use ffmpeg in Visual Studio 2013 C++ software (ultimately as part of an OpenCV project) - but right now I’m just trying to get basic FFMPEG functionality. In general, when building in Visual Studio, I build 64—bit software with Multi-threaded DLL runtime libraries. I have built ffmpeg using the general instructions for ’Native Windows compilation using ... MinGW-w64’ at http://ffmpeg.org/platform.html#Windows (I provide a more detailed set of steps I followed below...).

  After building the ffmpeg software on my system, I tried to create a simple ’hello world’ project in Visual Studio 2013. Specifically, I tried to implement the initial tutorial file presented at http://dranger.com/ffmpeg/tutorial01.html. Upon building the project, I get the error :

  c :\msys64\usr\local\ffmpeg\libavutil\common.h(45) : fatal error C1083 : Cannot
  open include file : ’libavutil/avconfig.h’ : No such file or directory

  The following are the detailed steps I took to build ffmpeg and create my basic Visual Studio project :

  ============ Building ffmpeg ===============

  1. Downloaded and intalled msys2-x86_64-20160205.exe from http://msys2.github.io
  2. Ran update-core to update the Msys2 install
  3. Ran pacman -Suu (twice) to complete the update (following the instructions about updating shortcuts, etc.)
  4. Then I quit out of the MSys2 shell and opened the MinGW-w64 Win64 Shell. In this new shell :
  5. Installed the following packages using pacman -S The list of packages I installed is : make, pkg-config, diffutils, mingw-w64-x86_64-yasm, mingw-w64-x86_64-gcc, mingw-w64-x86_64-SDL, git
  6. Then I cd’d into cd /usr/local
  7. Ran git clone https://git.ffmpeg.org/ffmpeg.git ffmpeg
  8. I wanted to build the ffmpeg library ’out-of-tree’ of this MSys64 folder. So, in the regular file system of my Windows machine I created a folder at C :\ffmpeg
  9. Back in the Win64 Shell, I cd’d to this new folder : cd /c/ffmpeg
  10. Then ran /usr/loca/ffmpeg/configure --enable-shared
  11. Then make -r
  12. And, finally make install

  Now, if I had to guess, my ’flaw’ was in the options I used when calling the ’configure’ script of ffmpeg. Do I need to use particular options so that I can take the ffmpeg libraries built here and use them as dynamic (DLL) libraries in Visual Studio ?

  ========== Configuring my Visual Studio Project ============

  Here’s how I created a simple hello world project in Visual Studio to see if ffmpeg is working.

  1. I created a new Visual C++ ’Empty Project’ in Visual Studio 2013

  2. I then configured the project properties as follows :

     a. In C/C++ => General => Additional Include Directories, I put

     C :\msys64\usr\local\ffmpeg

     b. In Linker=>General => Additional Library Directories, I pointed to each of the built library folders (basically I pointed at all of the libraries that were built to ensure I was not inadvertently missing the critical one). The list is as follows :

     • C :\ffmpeg\libavcodec
     • C :\ffmpeg\libavdevice
     • C :\ffmpeg\libavfilter
     • C :\ffmpeg\libavformat
     • C :\ffmpeg\libavutil
     • C :\ffmpeg\libswresample
     • C :\ffmpeg\libswscale
     • C :\ffmpeg

     c. In Linker=> Input => Additional Dependencies, I pointed to the particular libraries (again - I pointed to all of the ones present). The list is :

     • avcodec.lib
     • avdevice.lib
     • avfilter.lib
     • avformat.lib
     • avutil.lib
     • swresample.lib
     • swscale.lib

  3. I then created a new source file called ’tut01.c’ and copied/pasted the code from http://dranger.com/ffmpeg/tutorial01.c

  4. Then hit F7 and got the error specified above about not finding avconfig.h

  The above is my best guess as to the steps I need to follow to get this working in Windows (btw, it’s Windows 10, 64-bit) & Microsoft Visual Studio 2013. What should I change to get this basic program to build and run ?